string与QString转换（string既可以是utf8，也可以是gbk）

AtUtf8.h

#ifndef _QT_UTF8_H
#define _QT_UTF8_H

#include <QString>
#include <string>
using std::string;

class AfUtf8
{
public:
    // QString(Unicode) -> std::string (UTF8)
    static string ToString(const QString& qstr)
    {
        QByteArray arr = qstr.toUtf8();
        string cstr = arr.data();
        return cstr;
    }

    // std::string (UTF8) -> QString(Unicode)
    static QString ToQString(const string& cstr)
    {
        QString qstr = QString::fromUtf8(cstr.c_str(), cstr.length());
        return qstr;
    }
};
#endif

AtGbk.h

#ifndef _QT_GBK_H
#define _QT_GBK_H

#include <QString>
#include <QTextCodec>
#include <string>
using std::string;

class AfGbk
{
public:
    // QString(Unicode) -> std::string (GBK)
    static string ToString(const QString& qstr)
    {
        QTextCodec* pCodec = QTextCodec::codecForName("gb2312");
        if(!pCodec) return "";

        QByteArray arr = pCodec->fromUnicode(qstr);
        string cstr = arr.data();
        return cstr;
    }

    // std::string (GBK) -> QString(Unicode)
    static QString ToQString(const string& cstr)
    {
        QTextCodec* pCodec = QTextCodec::codecForName("gb2312");
        if(!pCodec) return "";

        QString qstr = pCodec->toUnicode(cstr.c_str(), cstr.length());
        return qstr;
    }

};
#endif

http://blog.csdn.net/bladeandmaster88/article/details/53469959